1. Field of the Invention
This invention relates to a waterproof connector having a waterproof means at a wire lead portion connected to a terminal in a connector housing.
2. Description of the Related Art
Japanese Patent Laid-Open Hei 1-121275 discloses a waterproof technique with respect to a waterproof connector having a sealing between a connector housing and a terminal wire portion accommodated in the connector housing.
The waterproof connector of this related art and the problems of the same will be described below with reference to FIGS. 13 and 14 of the accompanying drawings.
In this waterproof connector, a terminal 4 to which a wire 3 is connected is accommodated in a terminal accommodation chamber 2 of a connector housing 1, as illustrated in a longitudinal sectional view of FIG. 13. To prevent penetration of water at the terminal 4, a rubber plug 5 is provided for sealing between an inner surface of an inlet portion of the terminal accommodation chamber 2 and the wire 3.
As shown in FIGS. 13 and 14, the rubber plug 5 is formed so as to have a tubular shape with a plurality of annular projections 6 and 7 formed in its inner and outer peripheral surfaces, respectively. When the wire 3 is inserted into the rubber plug 5, the annular projections 6 are elastically deformed to be brought into close contact with the wire 3.
When the rubber plug 5 is inserted into the terminal accommodation chamber 2 together with the terminal 4, the annular projections 7 are elastically deformed and brought into close contact with the surface of the terminal accommodation chamber 2 to close the inlet of the terminal accommodation chamber 2, thereby achieving a waterproof effect.
The inside diameter of the annular projections 6 formed in the inner peripheral surface of the tubular rubber plug 5 is smaller than the outside diameter of the wire 3, since the projections 6 tightly contact the wire 3 by being elastically deformed.
A problem therefore arises in that if the diameter of the wire 3 is small, the diameter of a mold portion for forming the annular projections 6 by defining the inside diameter thereof is excessively small, so that the mold portion can be easily broken when it receives a certain lateral pressure.
However, if the diameter of the mold portion for forming the annular projections 6 is increased, a gap, such as a gap c shown in FIG. 14, is formed between the wire 3 and the annular projections 6 of the rubber plug 5, resulting in failure to prevent penetration of water into the terminal accommodation chamber 2 of the connector housing.